Gun firing mechanism with cutout device



Jan. 15, 1952 v. c. BOWSER ETAL GUN FIRING MECHANISM WITH CUTOUT DEVICE 4 Sheets-Sheet 1 Filed Dec. 9, 1946 INVENTORS I/IRG/L 6. BOWSER GERALD W K/IVZELMA/V ATTORNEY Jan. 15, 1952 V. C. BOWSER ETAL GUN FIRING MECHANISM WITH CUTOUT DEVICE 4 Sheets-Sheet 2 Filed Dec. 9, 1946 FIG. 2.

REUOT 01/750701? L.

ATTORNEY a w w u I 9 4 3 5 I Jan. 15, 1952 v. c. BOWSER ETAL 2,582,225

GUN FIRING MECHANISM WITH CUTOUT DEVICE Filed Dec. 9, 1946 4 4 Sheets-Sheet a FIG. 3

INVENTORS P/IRG/L 62 6053 55 1? GERALD EM KAWZELMAA/ BY Mam ATTORNEY Jan. 15, 1952 v. c. BOWSER EIAL 2,582,225

GUN FIRING MECHANISM WITH CUTOUT DEVICE Filed Dec. 9, 1946 4 Sheets-Sheet 4 VIII/III,

VIRG/L a GERALD E5! KIIVZELMAN BY j 9%? ATTORNEY GUN FIRING MECHANISM WITH CUTOUT DEVICE Virgil C. Bowser, Silver Spring, Md., and Gerald W. Kinzelm-an, Washington, D. C.

Application December 9, 1946, Serial No. 715,122

16 Claims.

(Granted under the act of March 3, 1883, as

amended April 30,

Gun firing mechanisms have been provided in the past with firing cutout devices which disable the firing mechanism when the gun is pointed at any portion of the vessel upon which the gun is mounted.

The firing mechanism is normally actuated by a pedal which closes the firing switch to initiate firing electrically when the pedal is partially clepressed and which fires through a mechanical linkage when the pedal is depressed further in the event of an electrical failure.

An electric switch stationed at a remote gun director is wired in series with the firing switch and firing will normally cease when either of these switches is open unless the pedal is depressed all the way.

The above-stated firing cutout. mechanism is provided with a switch in series with both the firing switch and the director switch and which is opened when the gun is pointed in a direction in which the firing is desired to be restricted. The firing cutout mechanism also opens a latch connection interposed between the foot firing pedal and the guns firing mechanism in order to break the mechanical connection between the two to prevent mechanical firing.

Accidents have occurred in the past due to the fact that when the director firing switch was open the gun continued to be fired by the mechanical linkage due to the pedal being held down all the way by the operator.

1. It is an object of this invention to provide means to stop firing when the director firing switch is open.

2. It is a further object to stop firing when the director switch is open, in such a manner that firing can be continued mechanically at the mount in the event of an electrical power failure, by releasing the foot firing pedal and then depressing it again.

3. It is a further object of this invention to provide in a gun having a manually operable firing device and a power operated firing device, a means to render the manual firing device inoperative while the power operated device is functioning.

4. It is a further object of this invention to provide in a gun having a manually operable firing device and a power operated firing device, a means to render the manual firing device inoperative which means consists of a breakable connection interposed in the manual firing device and adapted to be disengaged when the power operated means is in firing position, in such fashion that return of the power operated means to inoperative position cannot initiate firing by the manually operated means without further movement thereof by the operator.

5. It is a further object to employ the breakable connection of the firing cutout mechanism for the above-stated purpose.

6. It is a further object of this invention to provide a firing mechanism which employs a single switch which performs the functions of a firing cutout switch and a manually operated g firing switch.

7. It is a further object of this invention to provide a novel structure to accomplish the above-stated objects as shown in the drawing in which: r

Fig. 1 is a perspective view of a portion of a un mount embodying the invention;

Fig. 2 is an isometric projection which schematically illustrates one embodiment of this invention, the mechanism being shown in non-firing position and the arrows indicating the directions the parts move to fire the gun, portions of the gun engaged by this novel. firing mechanism also being shown;

Fig. 3 is a front elevation of the principal parts of the structure illustrated in. Fig. 2;

Fig. 4 is an end elevation. of the mechamsm in Fig. 3, and

Fig. 5 is a detail cross section taken on the line 5-5 of Fig. 4.

The foregoing objects are accomplished in the following manner, attention being directed first to the mechanism involved in Manual Firing: A pedal I is pinned to one end. of a shaft 2 consisting of several sections joined by universal joints 3. The end of shaft 2 opposite to the pedal is splined to a, hub 4; which rotates therewith. A

yoke 5 is mounted on the hub 43 by diametrically extending trunnions in the form of cap screws 6, in order to rotate yoke 5 with the hub and to permit movement perpendicular to this rotation. Yoke 5 has three integral arms 7, 8 and 9 whose functions will shortly be described. A bell lever I0 is freely journaled on shaft 2 for rotation with respect thereto and is spring urged clockwise by spring 56. Abutment surfaces H and i2 constituting a separable connection between levers HI and 7, respectively, inter-engage to rotate bell lever I ll counterclockwise when arm 1 is moved in this direction, providing the yoke 5 is in a position in which abutment surfaces H a and 12 are substantially in the same plane.

Abutment portion E3 on bell lever it! engages a firing arm 1 4 formed integrally with hub I5 which is secured to firing shaft I6. Because of its structure and free journaling the lever I0 is aptly called a floating clutch. Hubs it of lever arms I8 are splined to shaft U5. These arms rock bell levers H! by means of adjustable links 20.

Bell levers l9 have arms 2! which engage firing plungers 22 located in the gun trunnions 22a (see Fig. 1).

Said plungers extend inwardly of the gun trunnions where, at their ends, they are adapted to actuate conventional trigger mechanisms (not shown). The operation of manual firing involving the previously described mechanism is as follows. The gun pointers pedal l is depressed with his right foot through an arc of 28, turning the shaft 2 counterclockwise (Fig. 4:) and causing the hub i, carrying hinged lever 7, to pick up the floating clutch lever It. This is done after the first 10 of counterclockwise movement indicated 60. The abutments ll, l2 engage at that time.

From then on the lever H], which. it will be remembered is loose on the shaft 2, will be turned the remaining 18 to compose the total are of 28 indicated 6! in Fig. 4. The spring 56 will then be loaded. Clockwise turning of the firing arm l (Fig. 4) began with the movement of lever 10 after the engagement at H, i2, the abutment l3 and a similar abutment on lever It then leaving a bumper 76 (Fig. i) which is supplied and acts as an initial stop for and [4.

The aforesaid turning of the firing arm i4 rocks the right and left levers l8 clockwise, pullmg down on the links 20 and projecting the plungers 22 inwardly tofire the guns 62, 63 (Flg. l). Firing stops when the operator lets up on the pedal I, whereupon a spring 3'3 in a pedal-return assembly restores the pedal and its dependent parts to the initial position, the spring 56 doing the same for the floating clutch lever H0. The first 10 movement of the foot pedal I mentioned above, is for the purpose of permitting the closure of an electrical firing switch Electrical firing The gun may be fired electrically by depressing the foot pedal part Way, in actual practice about 7, by the following mechanism: Hub 4 has anintegral arm 23 having a camming surface 26 WhlOh normally rides on and depresses a roller 25 and arm 26 on which roller 25 is journaled. Switch member 2'1! is pivoted on pin 28 which is fixed in bracket 29. A spring 30 urges switch member 27 clockwise toward aclosed position in which contacts 3! on switch member 27, "engage and short circuit contacts MA in fixed contact strip 32-. The switch is thus closed by spring 3%! except when the foot firing pedal is released at which time arm 23 holds the switch open.

It remote director 57a is provided with a firing switch When the firing switch 3!, BIA and the remote director firing switch 51, which is wired in series therewith, are both closed, solenoid 34 is energized thus raising rod 35 attached to the solenoid lunger (not shown). Shaft 36 is rotated clockwise by this upward movement of rod 35, by means of a hub 3'8 fixed to shaft 36 and having an integral arm 38 pivoted to rod 35 by clevis 39. Fixed to shaft 36 is cam 0. Cam ill is a radial cam which rotates clockwise and lifts roller 42 journaled on arm {33, when the solenoid 34- is energized. Arm 43 is integral with hub l5 and firing thus occurs as explained for manual firing.

Firing cutout mechanism The firing cutout mechanism operates to prevent firing when the gun is trained and elevated into preselected non-firing zones. This mechamsm consists of a drum cam M rotated by the gun mount training circle 45, by any suitable gearing such as the pinion 64, worm 65, worm gear 66 and necessary shafting. The cam 44 will rotate 360 through 360 of training of the gun. A cam follower 45a is slidably mounted in a slide block as which is mounted in guides 46a (Fig. 3) for movement axially along the cam. This axial movement is caused by a rack 41 secured to block 45 and translated by pinion 48 which is rotated by the same gun elevating drive shaft 51 which actuates the elevating arc 49. For that purpose the drive shaft 67 has a bevel gear drive 68, 69 to a shaft it which, in turn, has a worm drive 1 I, 12 to a countershaft "it which carries the pinion 48. The drive shaft 5? also has a pinion 74 in mesh with the are '39. The actuation of the shaft. 8'! for elevating the guns $2, 63 thus also causes the reciprocation of rack 41. The maximum number of degrees of elevation is an index of the. extent of travel of the cam follower 45a along. the cam drum. In practice the contour of the cam is determined after the gun is mounted. on the ship, and at that time is profiled to demarcate areas intended to constitute the non-firing. zonesmentioned above.

A U-shaped frame 50, swingablymounted on a fixed stud 5i is moved counterclockwise by cam follower E5- when the latter is moved to the. right by high portions of cam 44. This cuts out electrical firing by means of a intle 52 secured to frame 5t and adapted to engage abutment 53 on switch member 2'! to open switch contacts. 3|,

31A, and thus de-energize solenoid 34. This allows spring 54 to rotate cam 40' counterclockwise to cease firing electrically.

Manual firing is also interrupted when follower ii c rides on a high portion of cam 44., since when frame 56 is swung counterclockwise by follower 45, it engages arm 8 of yoke- 5 to swing it counterclockwise about pivot 6, against the resiliency of compression spring 55. This spring 55 is supported in a bracket 5511 which is secured to hub 4. This will move arm 1 of yoke 5 counterclockwise about trunnions 6. and swin abutment surface :2 out of the path of surface H, to break the mechanical connection between the foot firing pedal and the gun. When the cam follower 55a returns to a low portion of cam i l, representing a safe firing zone, compression spring urges abutment surface. 12. toward realignment with surface i i. From what has been stated immediately above, it can be understood that the low parts of the cam 44 representv safe areas while the high parts represent danger areas. If the guns are either trained or elevated while the follower 55a rides the high part, both the electrical and manual firing facilities are suspended. A depression of the pedal I during that period will not yield any response, it being remembered that the mechanical connection between the pedal nd the firing shaft H5: is broken by the offsetting of the abutments H, l2.

Electrical and mechanical firing interlock Under this heading mention. is desired. to be made of a circumstance which can and does occur in. gun firing. The gun. pointer will: have depressed the pedal a distance commensurate with the 10 electrical firing zone 60 (Fig. 4) to permit closure of the switch 3I,.3I'A. At the same time the remote director switch 5'! will have been closed to in turn close theelectrical firing circuit. The gun starts firing electrically and thegun pointer, due to naturalfatigue, may inadvertently depress the pedal beyond the 10- intothe manual operating zone. Should it suddenly appear necessary to cease firing from the remote director prompting the opening of switch 51, but due to the position of the foot pedal the guns continue to fire under manual operation, use is made of a novel interlock which nullifies the foot pedal. This interlock comprises a cam 41 fixed to shaft 36 and rotated clockwise when the solenoid is energized.

Arm 9 on yoke 5 extends in back of and engages the rear surface of cam 4| which surface is formed as a face cam. As cam 41 rotates clockwise, as would occur during electrical firing, a thicker portion of cam 4! shifts push arm 9 and integral yoke 5 counterclockwise about pivots G to disengage abutment surfaces II and I2, so that arm 1 which is actuated by the inadvertent depression of the foot firing pedal, is moved out of range and becomes inoperative to move bell lever H] to fire the gun. If the foot pedal were held depressed at the lower limit of its travel while electrical firing was in progress due to director switch 5? being closed, arm 1 would remain at the end of its travel in a counterclockwise direction but its abutment surface l2 would remain out of the path of surface H on lever I!) because of the engagement of arm 9 with the high portion of cam M. This condition would permit spring 56 to rotate bell lever l5 clockwise, leaving a clearance space between abutment portion l3 and arm l4. If the director switch is then opened this clearance space will allow crank I4, I5, E3 to be rotated counterclockwise to cease firing position, by a spring in the gun mechanism (not shown) when spring 54 rotates cam 40 counterclockwise.

If it is then desired to fire the gun manually, it is necessary to permit the pedal to be returned to elevated position by spring 33.

Shaft 2 and arm I will then be rotated clockwise until abutment surface i2 thereof is abreast of surface i l on lever It]. at which time spring 55 will swing arm I and yoke 5 clockwise about pivots 6 to align surfaces I! and I2. Depression of the foot pedal will then result in manual firing as previously described.

It will be noted that the above-described arrangement permits the use of a single normally closed switch such as 3!, SIA which is opened either by elevation of the foot firing pedal or by the firing cutout mechanism, rather than by two separate switches as formerly used.

The invention herein described may be manufactored and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

We claim:

1. In a firing control system for a gun having a firing member, a firing linkage in operative engagement with said firing member, power operated means for actuating said firing linkage to fire said gun, manually operable means operatively connected to said firing linkage and operative alternatively with said power operated means to fire said gun, means responsive to movement of said power operated means to firing position to render said manually operable means inoperative, and means operative upon return of said power means to non-firing position to render the manually operable means operative to fire the gun only upon further movement of said manually operable means.

2. In a firing control system for a gun having a firing member, power operated means for firing said gun, manually operable means operatively coupled with said member for firing said gun, said manually operable means having a breakable connection in its operative coupling with said member, means responsive to movement of the power operated means to firing position to disengage said breakable connection to render said manually operable means inoperative, and means operative upon return of said power means to non-firing position to urge the breakable connection toward a re-engaged position to render said manually operable means operative to fire the gun upon further movement of said manually operable means.

3. In a firing control system for a gun having a firing element, a firing linkage in operative engagement with said firing element,.power operated means operatively connected to said firing linkage to actuate it and fire said gun, manually operable means also operatively connected to said firin linkage to a tuate it and fire said gun, said manually operable means comprising a firing pedal and a separable connection in the latter operative connection and consisting of a driving member and a driven member movable thereby with portions of both of said members in a common plane, driving means interposed between said driving member and said firing pedal, an operative connection between said firing linkage and said driven member, means responsive to movement of said power operated means to firing position to laterally move one of said members out of said plane to disengage said separable connection and render said manually operable means inoperative, and means operative upon return of said power operated means to non-firing position to urge said laterally movable member back toward said plane to render said manually operable means operative to fire the gun upon further movement of said firing pedal.

4. In a firing control system for a gun having a firing element, a firing linkage in operative engagement with said firing element, power operated means operatively connected to said firing linkage to actuate it and fire said gun, manually operable means also operatively connected to said firing linkage to actuate it and fire said gun, said manually operable means comprising a firing pedal and a separable connection in the latter operative connection and consisting of a driving lever and a driven leveractuated thereby, said driving and driven levers being pivotally mounted for movement in a given general direction, driving means interposed between said drivin lever and said firing pedal, an operative connection between said firing linkage and said driven lever, one of said levers being articulated for lateral rockable movement perpendicular to said given direction, means responsive to movement of said power operated means to firing position to rock said articulated lever laterally to disengage said separable connection and render said manually operable means inoperative. and means operative upon return of said power operated means to non-firing position to urge said articulated lever laterally back into engagement with the other of said levers to render said manually operable means operative to fire the gun upon further movement of said pedal.

5. In a firing control system for a gun having a firing element, a firing linkage in operative engagement with said firing element, power operated means comprising a rotary shaft for actuating said firing linkage to fire said gun, a cam on said shaft, manually operable means for actuating said firing linkage to fire said gun alternatively with. said power operated means, said. manually operable means comprising a firing. pedal and a coupling to the rotary shaft, a separable connection consisting of a driving lever and a driven lever actuated thereby, said driving and driven levers being pivotally mounted for movement in a given general direction, driving means interposed between said driving lever and said firing pedal, an operative connection between said firing linkage and said driven lever, one. oi said levers being articulated for lateralrock-able movement perpendicular to said given direction, an. arm on said articulated lever engaging said cam, said arm and cam being adapted to rock said articulated lever laterally upon movement of said power operated means to firing position, to disengage said separable connection and to render manually operable means. inoperative, and spring means operative upon return of said power operated means to non-firing position to urge said articulated lever laterally back into engagement with the other of said. levers to render said manually operable means operative to fire the gun upon further movement of said pedal.

6. In a firing control system for a gun having a firing element, a firing linkage in operative engagement with said firing element, power operated means for actuating said firing linkage to fire said gun, manually operable means for actuating said firing linkage to fire said gun, a firing cutout mechanism comprising a separable connection in said manually operable means, means operative when the gun is aimed in an unsafe direction, to sever said connection and thereby render said manually operable means inoperative, additional means. responsive to movement of said power operated means to firing position to disengage said separable connection to render said manually operable means inoperative, and means operative upon return of said power means to non-firing position to urge said separable connection toward a re-engaged position, to render said manually operable means operative to fire the gun upon further movement of said manually operable means.

7. Ina firing control system for a gun having a element, a firing linkage in operative engagement with said firing element, power operated means comprising a rotary shaft for actur ating said firing linkage to fire said gun, a, cam on said shaft, manually operable means for actuating said firing linkage to fire said. gun, and including a firing cutout mechanism comprising a separable connection in said manually operable means, means operative. when. the gun is aimed in an unsafe direction, to sever said connection and thereby render said manually operable means inoperative, said separable connection consisting of a. pivotally mounted driving lever adapted to be rotated by a firing, pedal, and a pivotally mounted driven member operatively connected to said firing linkage and adapted to be engaged by said driving lever andv rotated thereby to fire the gun, one of said levers being shiitably mounted for movement out of driving engagement with the other of said levers, an arm on said shiftable lever engaging said'cam, said arm and cam being adapted to shift said shiftable lever outof driving engagement withthe other of said levers, upon. movement of said power operated means to firing position to disengage said separable connection and render said manually operable means inoperative, and means operative upon return of said power operated means to non-firing position to: urge said shiftable lever back toward engagementwith the other of said. levers, to render said manually operable means operative to fire the gun upon further movement of said. firing pedal.

8-. In a firing control system for a gun having afiring element,. a firing linkage in operative engagement with said firing element, power operated means comprising a rotary shaft for actuating said firing linkage to fire: said gun, acam on said: shaft, manually operable means including av firing pedal attachedto the rotary shaft for actuating said firing linkage and fire said. gun, said manually operable means including a, firing cutout mechanism comprising a separable connectien', adapted to be disengaged when the gun is aimed in an unsafe direction, to render said manually operable means inoperative; said separable connect-ion consisting of a driving lever pivotally mounted on the rotary shaft and adapted to be: rotated by' thefiring pedal, and a. driven member rotatably mounted on the retary shaft, being: operatively connected to said firing linkage and. adapted to be engaged by said driving lever and rotated thereby to fire the gun, the pivoted mounting of the driving lever. enablin its movementout of driving engagement with the driven member, an arm on said driving lever engaging said cam, said arm and cam being adapted to shiftsaid driving. lever out of driving engagement withthe driven member upon movement of said power. operated means to firing position to disengage said separable connection and. render said. manually operable means inoperative, a drum cam, means to rotate saidcam in synchronism with said gun, a slide block, guide means mounting said slide block for movement longitudinally of said drum cam, a drum cam follower mounted on said slide block for movement radially of said drum cam, means responsive to elevation. and depression of the gun to slide. the slide block longitudinally of said cam, av second arm on said driving lever, means interposed. between said second arm and drum cam follower to move said second arm and said driving lever out of driving engagement with the driven member in response to movement of said drum cam follower by said drum cam in nonfiring zones to render said manually operable means inoperative, and means operative upon return of said power operated means to nonfiring position and upon return of said firing cutout mechanism to firing position to urge said driving lever back toward engagement with the driven member, to render said manually operable means operative to fire the gun upon further movement of said firing pedal.

9. In a firing. control system for a gun, power operated means to fire the gun, a firing pedal, an electrical switch controlling operation of said power operated means, said switch being spring urged toward a closed position in which the power operated means is operative to fire the gun, a firing cutout having means to open said switch when the gun is pointed in an unsafe di rection, cam means normally holding said switch open to prevent power firing, and means responsive to depression of 'said' pedal to move said cam means out of engagement with said switch to allow it to' close and fire the gun when the firing cutout permits.

10. In a gun firing control system, power operated. means for firing said gun, manually operable means for firing said gun, said manually operable means comprising a separable drive connection, an electric switch controlling operation or said power operated means, firing cutout means comprising a cam, means to move the cam in response to training of the gun, a cam follower engaging said cam, means to move said cam follower with respect to said cam in response to gun elevation, means responsive to movement of said cam follower by said cam when the gun is aimed in an unsafe direction, to disengage said separable drive connection and to open said switch to prevent firing by either manual or power means, and means responsive to movement of said power operated means to firing position, to disengage said separable connection.

11. In a firing mechanism for a gun having a firing element, a mount for a gun, a manually movable element located on the gun mount, mechanical linkage including a driving and a driven member in normal engagement and interposed between said manually movable element and said gun firing element and adapted to actuate the firing element to fire the gun when said firing element is moved to a firing position, an electric switch actuated by movement of said manually movable element, power firing means including a switch serially connected with the first switch, adapted to fire said gun in response to closing said first switch and means actuated by move ment of the power firing means to firing position, to disconnect the driving and driven mombers in order that the manually movable element may be rendered inoperative when the power firing means is in the firing position.

12. In a gun firing control, at least one firing plunger to cause firing of a gun, at least one linkage system connected to the firing plunger, power operated means for actuating the firing plunger, manually operated means connected with the linkage system for actuating the firing plunger, a floating clutch incorporated in said linkage system and including a driving member and a driven member initially in coupled relation to transmit a manual effort upon the manual means through said linkage system to the firing plunger, means operable by the act of starting the driving and driven members to restore the s operability of the manually operable means at the termination of power operaation.

13. In a gun firing control, at least one firing plunger to cause firing of a gun, power operated means for actuating the firing plunger, manually operated means for actuating the firing plunger including a shaft turnable by the manual operation, a linkage system connecting the manual means to the firing plunger, said system including the following, a firing arm, a lever loose on the shaft and being in abutment with the firing arm, a yoke mounted on the shaft to turn with it yet rock independently of it, and a separable connection initially coupled between a part of the yoke and the lever; and means operable by the act of starting power operation to rock the yoke and uncouple the separable connection thereby rendering said manually operated means inoperative.

14. In a gun firing control, at least one firing plunger to cause firing of a gun, power operated means for actuating the firing plunger, manually operated means for actuating the firing plunger including a shaft turnable by the manual operation, a linkage system connecting the manual iii means to the firing plunger, said system inch ing the following, a firing arm, a lever loose the shaft and being in abutment with the firi arm, a yoke mounted on the shaft to turn w it et rock independently of it and having a pi arm extending off from it to be shifted, anc separable connection initially coupled betweei part of the yoke and the lever; and a cam engz ing the push arm, operable by the act of starti power operation to shift the push rock 1 yoke and unoouple the separable connecti thereby rendering said manually operated mes inoperative.

15. In a gun firing control, at least one firi plunger to cause firing of a gun, power opera1 means for actuating the firing plunger, manua operated means for actuating the firing plum including a shaft turnable by the manual ope] tion, a bracket afiixed to hence turnable with i shaft, a driving member turnable with t shaft and rockable independently in respect it, a linkage system connecting the filil plung with the shaft, said linkage system including driven member loosely mounted on the shaft separable connection between the driving a driven members being initially coupled togeth means operable by the act of, starting power c eration to rock the driving member and so sh said separable connection to sever the driv from the driving member, and means based the bracket and engaging a part of the drivi member, being put under stress by the rocki of the driving member later to restore the opei bility of the manual means at the terminati of power operation.

16. In a gun firing control, at least one firi plunger to cause firing of a gun, manual mea with linkage to the plunger, said manual mea being movable into a first position, electrical pc or means with linkage also to the plunger for ele trically operating the plunger, an electrical c3 cuit containing the power means and having first closable switch, a second switch in said 01 cuit closable by assumption of said first positi by said manual means, thereby to complete t circuit and actuate the plunger by the electric power means to fire the gun, said manual mea being movable at some other time into a secoi position to mechanically fire the gun, and d1 connect means operated at the closure of ti first switch and. by the ensuing electrical pow operation to sever the manual linkage and th prevent possible continued manual mechanic firing upon a sudden requirement to cease fire by opening of the first switch.

VIRGIL C. BOWSER. GERALD W. KINZELMAN.

REFERENCES CITED The following references are of record in t1 file of this patent:

UNITED STATES PATENTS Number Name Date 658,704 Dawson et a1 Sept. 25, 191 1,651,699 Halsey Dec. 6, 19! 2,135,688 Wright et al Nov. 8, 192 2,380,611 Quinnell et a1. July 31, 194 2,408,277 Soenke Sept. 24, 194 2,434,654 Watkins et al Jan. 20, 194

FOREIGN PATENTS Number Country Date 516,623 Great Britain Jan. 8, 194 545,353 Great Britain May 21, 194

Unm- 

